A wide variety of radioactive isotopes are used for medical, industrial, research, and commercial applications. In general, radioisotopes may be produced by irradiating target isotope materials with nuclear particles. The target atoms either transmute directly into the desired isotope, or a radioisotope is produced through a chain of absorption and decay that subsequently generates the desired radioactive product.
Two different technologies are used to provide the source of radiation for radioisotope production: nuclear reactors, which produce a flux of neutrons; and particle accelerators or cyclotrons, which produce a flux of charged particles, usually protons, but sometimes electrons or other particles. For example, medical and industrial radioisotopes have been produced since 1957 by Canada's National Research Universal (NRU) reactor at the Atomic Energy of Canada's (AECL's) Chalk River Laboratories in Ontario, Canada. The NRU produces a high percentage of the world's medical and industrial radioisotopes, including molybdenum-99, a critical isotope used for medical diagnoses. Other exemplary radioisotopes used for medical, industrial, research and commercial applications include thallium-201, which is used for medical cardiac imaging; calcium-44, which is used in bone growth studies; iridium-192, which is used for nondestructive testing of construction and other materials; cobalt-60, which is used to destroy cancer cells, to disinfect surgical equipment and medications, and the sterilization of food supplies; thulium-170, which is used for portable blood irradiations for leukemia, lymphoma treatment, and power source; gadolinium-153, which is used for osteoporosis detection and SPECT imaging; nickel-63, which can be used for the creation of long-life batteries; and americium-241, which is used in smoke detectors.
In general, specimen rods containing an isotope target are inserted through penetrations in the NRU in a continuous process and subject to irradiation therein, so as to produce isotopes at a desired specific activity for use in nuclear medicine and/or industrial applications. The isotope targets are then irradiated during operation of the power generating nuclear reactor. After irradiation, the radioisotope is recovered from the target and used for preparing various radiopharmaceuticals for nuclear medical procedures.